Are there any reasonably accurate ways to determine how much powder will burn in a certain barrel length? Here is my situation: I made a smokeless muzzleloader out of a Savage 110 action and added a #7 .458 barrel with a breechplug that uses a 45 acp case for the primer. I am trying to work up a load for a 150 grain 30 cal SMK/Accubond/SST/A-Max The sabot weighs 42 grains bringing the total weight to 192 grains. My main problem is with choice of powders. 1) I need a stick powder so that it does not fall through the hole in the breechplug; 2) the bullet/sabot offers VERY little initial resistance; 3) 22 1/2 inches of usable barrel length, this INCLUDES the powder area; 4) I would prefer to not duplex powder. It has worked well but if one powder will work I prefer that. 5) 50,000 psi working load would be preferred (55k max) Now the problem: When I get a powder to a meaningful load the muzzle blast becomes excessive and the accuracy goes to heck ( presumably due to not burning the powder soon enough). 60+ grains of H4198 is about max 65 grains of N120 the same( I thought that this should be a good range of powder). N110 was still good @ 60 grains but I ran out of time. So my real question is, do I just proceed by trail and error in figuring if a powder will burn completely in this short tube? Any help will be greatly appreciated. edge.